/*
 * Copyright (c) 2024 Huawei Device Co., Ltd.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import path from 'path';
import fs from 'fs';
import { FileNotFoundError } from '../error/error';

export function which(cmd: string): string {
    let pathEnv = [];
    if (process.env.PATH) {
        pathEnv.push(...process.env.PATH.split(path.delimiter));
    }
    pathEnv.push(process.cwd());

    let pathExt = [''];
    if (process.env.PATHEXT) {
        pathExt.push(...process.env.PATHEXT.split(path.delimiter));
    }
    
    for (const _path of pathEnv) {
        for (const ext of pathExt) {
            let file = path.join(_path, `${cmd}${ext}`);
            if (fs.existsSync(file)) {
                return file;
            }
        }
    }

    throw new FileNotFoundError(`${cmd} not found.`);
}
